/*
  Licensed to the Apache Software Foundation (ASF) under one
  or more contributor license agreements.  See the NOTICE file
  distributed with this work for additional information
  regarding copyright ownership.  The ASF licenses this file
  to you under the Apache License, Version 2.0 (the
  "License"); you may not use this file except in compliance
  with the License.  You may obtain a copy of the License at

    http://www.apache.org/licenses/LICENSE-2.0

  Unless required by applicable law or agreed to in writing,
  software distributed under the License is distributed on an
  "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
  KIND, either express or implied.  See the License for the
  specific language governing permissions and limitations
  under the License.
 */
package org.flowable.osgi;

import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;
import java.util.Map;

/**
 * Utility class to parse a standard OSGi header with paths.
 *
 * @version $Rev$, $Date$
 */
public class HeaderParser {

    /**
     * Parse a given OSGi header into a list of paths
     *
     * @param header the OSGi header to parse
     * @return the list of paths extracted from this header
     */
    public static List<PathElement> parseHeader(String header) {
        List<PathElement> elements = new ArrayList<>();
        if (header == null || header.trim().length() == 0) {
            return elements;
        }
        String[] clauses = header.split(",");
        for (String clause : clauses) {
            String[] tokens = clause.split(";");
            if (tokens.length < 1) {
                throw new IllegalArgumentException("Invalid header clause: " + clause);
            }
            PathElement elem = new PathElement(tokens[0].trim());
            elements.add(elem);
            for (int i = 1; i < tokens.length; i++) {
                int pos = tokens[i].indexOf('=');
                if (pos != -1) {
                    if (pos > 0 && tokens[i].charAt(pos - 1) == ':') {
                        String name = tokens[i].substring(0, pos - 1).trim();
                        String value = tokens[i].substring(pos + 1).trim();
                        elem.addDirective(name, value);
                    } else {
                        String name = tokens[i].substring(0, pos).trim();
                        String value = tokens[i].substring(pos + 1).trim();
                        elem.addAttribute(name, value);
                    }
                } else {
                    elem = new PathElement(tokens[i].trim());
                    elements.add(elem);
                }
            }
        }
        return elements;
    }

    public static class PathElement {

        private String path;
        private Map<String, String> attributes;
        private Map<String, String> directives;

        public PathElement(String path) {
            this.path = path;
            this.attributes = new HashMap<>();
            this.directives = new HashMap<>();
        }

        public String getName() {
            return this.path;
        }

        public Map<String, String> getAttributes() {
            return attributes;
        }

        public String getAttribute(String name) {
            return attributes.get(name);
        }

        public void addAttribute(String name, String value) {
            attributes.put(name, value);
        }

        public Map<String, String> getDirectives() {
            return directives;
        }

        public String getDirective(String name) {
            return directives.get(name);
        }

        public void addDirective(String name, String value) {
            directives.put(name, value);
        }

    }
}
